Hemodynamic Correlates of Distinct Hypnotic States

Despite the growing number of studies investigating of the physiological underpinnings of hypnosis by means of neuroimaging methods such as electroencephalography (EEG) positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), still no consensus exists regarding the underlying neurophysiological working mechanisms due to high levels of variability in the data.

Generally, the variability observed in research examining the neurobiological fundamentals of hypnosis could be attributed to the following characteristics:

• Heterogeneity regarding hypnotic induction procedures.
• Insufficient statistical power.
• Mono-Modality: Studies investigating the neurophysiologic mechanisms of hypnosis typically apply only one method for the investigation of their research questions. However, different techniques complement each other, hence, resulting in a more thorough understanding of the mechanisms of action.

In this project, the investigators present a multimodal approach, in which these three points are considered in order to provide a comprehensive picture with respect to psycho- and neurophysiologic fundamentals of hypnosis and proposed distinct hypnotic states.

Point 1) will be approached by applying a highly reproducible method for the hypnotic induction (OMNI-hypnosis). This hypnosis method is fast, direct and all OMNI educated hypnotherapists follow exactly the same induction procedure. This implies a high level of standardization and operationalization, crucial prerequisites to investigate the phenomenon based on scientific guidelines.

Point 2) will be addressed by including a homogeneous study sample of 50 highly suggestible participants. Furthermore, the comparably high number of 50 participants should ensure sufficient statistical power particularly in consideration of the homogeneity of the study sample.

Point 3) is addressed by following a multimodal approach combining a vast array of psychophysiological measures with multimodal neuroimaging. For that purpose, the project will be divided into three studies: A EEG- and psychophysiological study, a fMRI-study and a magnetic resonance spectroscopy (1H-MRS) study.

In the present study, fMRI is applied for the investigation of network dynamics associated with hypnotic states. Hypnotic states will be compared to control states which follow mock instructions matched to the hypnosis instructions.

Inclusion criteria

• Aged between 18 and 65
• Proficient in German language
• Written informed consent after being informed
• Familiar with hypnotic states of OMNI-Hypnosis

Exclusion criteria

• Pre-existing neurological and/or psychiatric conditions
• History of brain injuries
• Alcohol and/or drug abuse
• Chronic diseases that require a permanent intake of drugs

Additional exclusion criteria for the MRI- and 1H-MRS-experiment:

• General contraindications for a participation on a MRI-Experiment (e.g. claustrophobia, pace maker, cochlea implants, insulin pumps)
• Hypersensitivity to loud noise
• Not being able to lie still during a longer period of time
• Foreign metallic objects in the body (e.g. gunshot wounds, metallic particles, metal implants, irremovable piercings)
• Pregnancy